TheSamba.com :: View topic

Fri Jan 17, 2014 2:34 am

Hi there, I am wondering how nasty of a 1600 I can build, I can not go over 1600cc though.

I am not limited to anything else, so high compression, high RPM, etc etc

i don't really know anything about these motor's except that my old 1200 didn't enjoy 7,500 RPM very much haha cracked all the rings on the left side, and exploded a rod bearing inside

I have been looking around, but all these sites give are stock rebuilds, or a performance engine, with no price. I am expecting to spend 5000 or more on the motor, and I would still need ignition, clutch/flywheel, transmission, and all that good stuff.

I should note on what I am racing...

It is called a Swamp buggy, it is a 1600cc max air cooled class, it need to be 1, 2, 3, or 4 cylinder 1600cc and has to be air cooled.

here's a video for those who don't know what it is. Everyone uses motorcycle motors, I was one of the last 2 to use a VW motor.

http://www.youtube.com/watch?v=dhFGIihAzZg

You guys/gals will love it haha I know the VW can dominate, it has before.

Fri Jan 17, 2014 3:13 am

Engine spec:
Case: original AS41
Crank:German stock
Rods:German stock
Pistons:JE 86mm 24mm comp hight
Cylinders:Stock 85,5mm honed to 86mm
Heads:043 40x32mm valves
Compression:12,0:1
Rockers:Jpm two stud 1,5:1 ratio
P-rods:Manton 3/8" cromoly
Cam:Fk45in/Fk44 ex
Cam gears:Magnum
Oilpump:26mm
Deepsump:1,5lit
Flywheel:180mm stock lightend
Clutch disc:cush lock
Pressure plate:Kennedy
Header:Custom made 1 5/8" tuned length
Manifolds:Custom made tuned length(second order)
Carbs:IDA 48

jpm mighty mouse 1600. made roughly 200hp @8000rpm.

I'm just embarking on another 1600 engine build, trying to see how close i can get to that engine above.. follow 'another engine build' for details.

Fri Jan 17, 2014 3:37 am

I must be mistaken on what I've heard, 8000rpm on stock crank/rods? I thought that was impossible?

I shall go follow that build thread!

Fri Jan 17, 2014 4:02 am

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Fri Jan 17, 2014 4:08 am

tegwin wrote: I must be mistaken on what I've heard, 8000rpm on stock crank/rods? I thought that was impossible?

!
Because it is.

You're pushing your.luck spinning a stock crank past 5500 rpm.

that's not a "stock" crank.

Fri Jan 17, 2014 4:24 am

Glenn wrote: tegwin wrote: I must be mistaken on what I've heard, 8000rpm on stock crank/rods? I thought that was impossible?

!
Because it is.

You're pushing your.luck spinning a stock crank past 5500 rpm.

that's not a "stock" crank.

Just inquiring glenn, but what have they done with the crank then? It was in a post on here that its a stock crank just balanced and 8 doweled?

Fri Jan 17, 2014 4:24 am

oh, I guess I have a steep learning curve with these motors haha

Fri Jan 17, 2014 4:40 am

stock crank..

the JE piston was about half the mahle piston weight 85.5mm bore

the lighter piston weight and the lightened stock rods

made it OK to run a stock crank etc...

while it may seem enticing and cool to run stock crank (saves cost)

a 700$ custom piston from JE isnt cheap LOL

IMO someone can do a build similar to JPM just a few clicks below that level of tune..

85.5x69
-counterweight/welded crank from DPR (195$)
-cb unitech ibeam rods at below 140$ its a good choice and
(90g lighter than stock 311b rods)
-have a porter do 37.5x33 intake valves ported and all
- engle w120 or web110 with 1.25 rockers
dual 44idf's

might not make 200hp not even 170hp
but
Alstrup has made 110hp on a milder set up thats more street friendly
heres a link (2nd to the last post on page5)
http://www.thesamba.com/vw/forum/viewtopic.php?t=435993&start=80
so a step higher than his and 120-130hp is def possible

BUT

Fri Jan 17, 2014 4:42 am

I don't need anything remotly street friendly, I am probably going to buy some EFI heads, I looking through every rule in the book and there is no stated carburetor rule for my class, so I -technically- can run a EFI system

Fri Jan 17, 2014 4:53 am

tegwin wrote: I don't need anything remotly street friendly, I am probably going to buy some EFI heads, I looking through every rule in the book and there is no stated carburetor rule for my class, so I -technically- can run a EFI system

efi heads have small valves and all..

not necesarily wow power maker...

unlike honda and toyota u need to run efi head to run efi..

any type1 head on the market.. wont care wat induction/fuelling u run..
044 heads
049 heads
040 stock heads etc

food for thought...

and i can understand u dont need anything remotely street friendly
but JPM builds engines and designs engine parts..

you got to start on something mild to understand where ur headin to...

Fri Jan 17, 2014 5:02 am

I started with a stock 1200cc, so stepping up to 1600 and at least being able to spin it high would make me happy

Fri Jan 17, 2014 5:33 am

The crank in JPM´s mouse motor is stock apart from softening the edges and SPG dowels. WRT weight and flex as Ralf wrote.
A CW crank Will make the case live significantly longer, but will also add reciprotating weight. Part of succes of this build is lightweight parts.

I do not believe there are any off the shelf heads available that will fit the bill on such a build. They need to be portet and treatet to "this" build.
Depending on how much torque is needed over hp 140 - 170 hp is relatively easy within reach.

I also doubt that 5 grand will cover the build, especially not if you need some serius EFI

T

Fri Jan 17, 2014 5:37 am

look at the link of the engine build in this forum i linked you to..

if you're coming from a 1200cc
the 110hp that alstrup built would be a huuuge step up
as far as competition...

believe me.. my daily was a 1200cc
now its a 1679cc stock everything except for the 88mm and singleport heads i ported , stock carb even (30pict3)

and that was night and day difference to my old 1200cc :)

Fri Jan 17, 2014 5:50 am

I would look way outside the box and build a large bore small de-stroked engine. Power is in the heads. With larger pistons you can run larger valves. Your going to spend $2500 on a set of heads that will win you races.

Fri Jan 17, 2014 6:27 am

vwracerdave wrote: I would look way outside the box and build a large bore small de-stroked engine. Power is in the heads. With larger pistons you can run larger valves. Your going to spend $2500 on a set of heads that will win you races.

he is coming from a 1200cc..

budget of 5000+ i suppose if he can spend over 10 grand he would have said budget of over 10,000 but ... he didnt

if he did well on a 1200cc then i think its okay to run a Hot 1600

no need to go exotic

Fri Jan 17, 2014 3:25 pm

Well,...... a destroked crank need not cost much more than a regular CW crank. But there is not much need. The stated 140-170 hp is no problem to find with the 85,5 mm bore. And I for one would definitely keep the stroke to get a better power band.

T

Fri Jan 17, 2014 3:57 pm

Basically you are trying to combine two opposing design goals into one - long life and response for the street, max power with little regard to cost, life or drivability for the track.

You are going to have to decide where you want to be and start from there.

Fri Jan 17, 2014 4:07 pm

Oh never mind..... Edited to ZIP, failure to read and comprehend....... Gads I hate old age.........

Dale

Fri Jan 17, 2014 4:13 pm

Heads heads and more heads
shortttt skirt lighten pistion
some short aluminum rods (the right ROD BOLT)

Fri Jan 17, 2014 4:25 pm

Quokka42 wrote: Basically you are trying to combine two opposing design goals into one - long life and response for the street, max power with little regard to cost, life or drivability for the track.

You are going to have to decide where you want to be and start from there.

I don't think anyone read the OP's post, he's building a racing motor not for the street, with a limit of 1600, so of course someone in an 1835 would beat him, if they were allowed to race

just get a C/W crank, balance everything(professionally), lightened flywheel, and match carb(s)carefully with cam for the power band you'll be in most

making sure everything is in spec, and fits right, will provide a long lasting motor, even at high revs

VWracerDave, is actually right, destroking and bigger pistons will allow better heads, which will allow better power, but that comes at a major cost